1. Field of the Invention
This invention relates to long chain polyunsaturated hydrocarbons, derivatives, and uses thereof, methods of preparing the long chain polyunsaturated hydrocarbons and compositions comprising the polyunsaturated long chain hydrocarbons. The present method is also useful for preparing C12-26 alkyl esters and C12-26 carbon chain compounds containing a terminal olefin.
2. Related Art
Hydrocarbons are generally derived from crude oils. When crude oil is cracked, the different components in the oil are distilled and separated. Many of the fractions produced from the cracking process contain long chain hydrocarbons. These chemicals are widely used in industry and are found in innumerable products. Because crude oil is a non-renewable resource, alternative sources of long chain hydrocarbons are desirable.
Vegetable and animal oils are a source of long chain hydrocarbons. Vegetable oil fatty acids contained in the oil have carbon chains up to about 26 carbons in length. Thus, these oils can be useful sources of long chain hydrocarbons. Fish oils are enriched in long chain polyunsaturated fatty acids. However, the hydrocarbons are in the form of fatty acids, fatty acid esters or other forms that are used in biological processes.
Hydrocarbon chains derived from fatty acid salts are known in the art. Electrocoupling of fatty acid residues produces hydrocarbon chains (Vogel, A. I., Experiment 5.11 Hexacosane, in Vogel's Practical Organic Chemistry, 5th Ed., Eds. Furniss, B. S. et al., John Wiley & Sons, Inc., NY., 1989, p. 484; Weiper-Idelmann, A., et al., Acta Chemica Scandinavica, 52, 1998, 672-682; Schafer, H. J., Chemistry and Physics of Lipids, 24, 1979, 321-333. Methods known in the art yield saturated chains that are relatively short in length. Electrocoupling of polyunsaturated long chain fatty acids from oils, specifically vegetable oils, to produce long chain hydrocarbons that can be further derivatized has not been utilized.
Soapstock is an inexpensive source of vegetable oil fatty acids. When glyceride oils, e.g., animal fats or vegetable oils, are refined to remove free fatty acids and other impurities by alkali refining, the aqueous alkaline solution which is separated from the bulk of the refined oil contains alkali soaps of fatty acids together with substantial quantities of free fatty acids, glycerides thereof, and various impurities including water-soluble phosphatides such as lecithin. Some of the free fatty acids, glycerides, and impurities ordinarily will be emulsified in the resulting aqueous mixture by the soaps and the phosphatide-type components. This aqueous mixture is commonly known as “soap stock”. Alternate, less refined or recycled fatty acid feedstocks are available. These feedstocks include acidulated soap stock (acid oils), used grease from restaurants, and all other acylglyceride esters of fatty acids that contain high levels of free fatty acids (FFA).